The proposed research is directed at analyzing how visual experience affects the development of binocularity of the frog optic tectum. Physiological and morphological techniques will be used to compare the connectivity of the ipsilateral visuo-tectal projection in normal frogs with that seen in animals in which the project has been altered by experimental manipulation of early visual experience. This is intended to show what aspect of the adult projection is affected by early visual experience. The effects of the ipsilateral visuo-tectal projection in the adult of varying degrees of pre-metamorphic eye rotation will be compared in Xenopus laevis and Rana pipiens. An explanation for expected differences in these effects in the two frogs will be sought in a comparative study of the normal development of the ipsilateral visuo-tectal projection in each. Inferences about changes in connectivity occurring in normal development and how they are affected by experience will be drawn from these studies. Finally, the possible reversibility of the effects of monocular deprivation will be investigated in adult Rana. This may make possible a direct demonstration of the changes during the normal developmental process inferred from other studies.